The subject matter described herein relates generally to methods and systems for operating a wind turbine or a wind farm, and more particularly, to methods and systems for operating a wind turbine or a wind farm under noise management.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extend from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
During operation of such known wind turbines, rotational transiting of the blades through air generates aerodynamic acoustic emissions in the form of audible noise. These acoustic emissions may produce noise with a decibel (dB) level that may approach or even exceed local regulatory levels. Accordingly, at least some methods exist for controlling noise from a wind turbine or a wind turbine installation including a plurality of wind turbines (i.e., a wind farm). In particular, a wind turbine may be operated such that produced noise is below predetermined dB parameters. Such an operation of a wind turbine for reducing acoustic emissions is also known as noise reduction operation (NRO) or operation under sound power management (SPM).
NRO typically implies that a wind turbine generates an electric power below the maximum possible power generation capacity of the wind turbine. Therefore, the operational state of a wind turbine under noise reduction operation is normally not directed to achieve a maximum power output but to comply with noise regulations applying to the wind turbine. However, during SPM, it is important to still yield the maximum amount of electric power that is possible under the prescribed regulations.
In practice, however, it turns out that the operation under SPM does not always lead to the desired results. In some cases, the resulting generated power is below that of what could be expected given the allowed noise power level. In yet further situations, the resulting noise does still exceed the allowed level although it should not. Hence, it is a desire to improve the operation under SPM, in particular, it is a desire to increase the power output of a wind turbine or a wind farm operating under SPM. It is also particularly desirable that the noise regulations are met during operation under SPM.